


Tantric Magic

by GrandLeviathan



Category: Fate/stay night & Related Fandoms
Genre: Anal Sex, Blow Jobs, Consensual Sex, Creampie, Double Penetration, Dubious Consent, F/M, Filming, Gangbang, Hand Jobs, Kissing, Light Masochism, Magical Contracts, Prompt Fic, Smut, Spitroasting, Vaginal Fingering, Vaginal Sex, porno
Language: English
Status: Completed
Published: 2020-08-07
Updated: 2020-08-07
Packaged: 2021-03-06 00:20:04
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 4,573
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/25764295
Author URL: https://archiveofourown.org/users/GrandLeviathan/pseuds/GrandLeviathan
Summary: After messing up a big experiment and with nothing good to show for it, Rin Tohsaka finds herself in debt to the lord she served under - and one who had a good idea on how to make her repay her debt.
Comments: 62
Kudos: 35
Collections: Zfatehentai





	Tantric Magic

**Author's Note:**

> For context, Rin is wearing her standard red-sweater-black-skirt outfit she does in Fate Stay Night, since I'm assuming that's her default outfit.
> 
> Enjoy~

The Clocktower was a respected and prodigious organisation.

It was a place where many people honed their talents and refined their skills, practising magic for years if not decades on end. However it was also a very cut-throat organisation, one where political ties were made and severed on a regular basis. High-ranking lords took younger apprentices under their wings, used them for their own gain and then threw them aside the moment they weren't needed.

Some lords were more kinder than others. Rin Tohsaka had mentored under one such 'kinder' lords. Though, that did little to abate his displeasure where she botched up a massive experiment.

''I'm very disappointed in you, Rin. I had high hopes after you presented your theory on interweaving mana threads.''

Rin kept silent, head bowed as she knelt down on the rough stone floor of Lord Aiselheim's personal quarters. The experiment had been a complex one, and one that required a lot of funding; hence why she even enlisted Lord Aiselheim's services in the first place. And so when she accidentally got too excited, she ended up causing a chain reaction that utterly obliterated the entire experiment, including all her research notes. All that money, wasted, and she had literally nothing to show for it.

It was a small mercy she herself wasn't caught in the combustion, but at that moment she was seriously regretting not getting herself injured. Maybe then he'd have more sympathy for her screw-up.

''In light of your _mistake-_ '' Lord Aiselheim put more emphasis on that last word, smiling down at her kneeling down amusedly. ''-I will invoke the magical contract that you signed, as per our agreement. As reparations for your loss of goods, you will have to assist me in one of my little... side ventures, until such a time the debt is paid off. Do you understand this, Rin Tohsaka?''

''Yes, I understand.'' Rin sighed. Considering Lord Aiselheim's track record, she imagined she'd be spending the next few months as a research assistant or something. Boring work, but at least it wouldn't be dangerous. Cruel lords would probably have made her the guinea pig; perhaps literally.

The tall lord smiled sharply down at her. ''Good. One branch of magic I've been quite invested in happens to be tantric magic – yes, the kind of magic Succubi were known for, and the type of magic usually generated during sex. I'm sure you know where I'm going with this, don't you?''

Rin was shaking her head furiously before he even finished. ''I-I'm not having _sex_ with you!''

''Oh no, don't worry.'' Lord Aiselheim chuckled lightly. ''I have no interest in you that way. However, considering your magical ability and your youth, you are the perfect subject for such experiments. I'll enlist the help of some other male magicians, you let them do what they wish to your body and make them feel good, and I'll happily take notes off the side. A sound deal, don't you think?''

''I- _I'm not a prostitute!_ ''

The lord was unfazed by her shout, retaining his light smile the whole time. ''Of course you aren't. You're a _research assistant._ I'll be sure to put on your résumé that you were a helpful researcher, make no mention of _how_ you researched it – and if the results are satisfactory, I _might_ even share some of my gained knowledge with you to keep, free-of-charge.''

Rin moved her mouth, but the lord continued. ''And need I remind you that _you_ were the one who failed your end of the contract in the first place. Please, don't make me force you into this.''

The twin-tailed magician hesitated, rolling the options around her mind – before with a deep sigh and gritted teeth, Rin agreed.

''Excellent!'' Lord Aiselheim clapped his hands together with a smile. ''I'll give you the details tomorrow morning; please be at the assigned location in the evening.''

Rin growled out an agreement, and soon departed the room for her own quarters.

X-x-X

The next night, Rin found herself standing outside a hotel door.

A rather decent hotel door, admittedly; the hallway around her lavish and as 5-star as one might expect from someone as rich as Lord Aiselheim, but the grandeur of the building did little to dispel her lingering anxieties. Still she was too stubborn to let her worries get the best of her, reminding herself that she had to do her best due to the Geis put on her.

Breathing in one last sigh Rin grasped the handle, and stepped inside. The luxurious hotel room had an amber-beige hue to it, dimly lit but not so much it made it hard to see. A king-sized bed was located between two bedside cabinets, but aside from a few other minor furnishings, the room was barren – leaving nothing to distract her from the three older men waiting for her, all of them in their boxers and shirts.

''Hmph.'' Rin crossed her arms, stepping inside. ''So, when are we starting?''

The three nameless men looked between each other, before the one in the back nodded and clasped his hands together, murmuring under his breath. A spherical drone-camera floated up from a nearby table and activated, the magical construct focusing on her as it began to _record_ her – the thought making her grimace internally; mindfully keeping her face blank.

Footsteps made her glance over at the men, a blush dusting her cheeks as one wrapped his arm around her lower back, pulling her up against his chest – and before she could form a single syllable, he crashed his lips against hers. The sudden rough kiss made Rin squeak, cheeks rapidly reddening as his rough lips meshed against her own softer ones. With a shudder Rin reluctantly found herself kissing him back, groaning embarrassedly into the kiss.

''Mm?!'' A sudden squeak shot out her throat as a hand grabbed her ass – prompting Rin to retreat from the kiss, shooting a startled look over at one of the other men.

The man smirked at her, gripping her ass in a tight grip. Rin shivered as her lips were reclaimed by another man, all three of them surrounding her on all sides – one grabbing her ass, another squeezing her thigh and a third grabbed her chest. Her bra muffled the feeling of the man's groping hands but not entirely, his meaty fingers squeezing the breath out of Rin bit by bit, leaving her gasping between kisses as she tried to keep a level head.

That was made nigh-impossible when one of the men abruptly moved his hand under her black skirt, his fingers tickling her fleshy inner-thighs – before he shoved his hand into her black panties. Rin gasped and her eyes went wide, intimately aware of the probing digits stroking her pussy. However the Geis prevented her from retaliating, leaving Rin able to only whimper as the man rubbed her off, his fingers thick as they poked between her folds

''Nn...'' Rin groaned as the fingers wriggled inside her womanhood; two thick fingers stretching her insides slightly.

The twin-tailed girl barely had the time to gasp in a breath before another man kissed her, devouring her low groans of embarrassment and groping her breasts roughly. The third man occupied himself with sniffing her hair and groping her ass and thighs, his rough touch making her reflexively arch her body away but her position made it impossible to move away; especially when two thick fingers were worming around her insides, sparks of unwanted pleasure teasing her pelvis.

''Mn... ah~'' Rin's cheeks darkened when she let out a soft _moan_ – the humiliation of making such an embarrassing sound in front of a bunch of old men, strangely _turning her on._

Rin had no time to contemplate her embarrassing reaction before the man abruptly pulled his fingers out of her pussy, and to Rin's mortification his fingers were wet. Any thoughts about her wetness however took a back-seat as one of the men moved behind her, his hand leaving her ass a moment before he grasped the bottom of her red sweater and yanked it up. Both her arms were forced up with it, embarrassment pooling in her stomach as the man took it off; revealing her white shirt underneath.

In what felt like seconds two of them went to town on her skirt, their heavy breathing thick in her ears as they ripped the buttons open one by one, soon ripping her shirt open completely to display her lacy red bra. Rin winced as they jerked her arms back, pulling her white skirt off and leaving her topless aside from her bra, her embarrassment heightening when the camera subtly floated above them to get a good look at her cleavage.

''Hah...'' Rin shuddered as two of them men slid their hands up to her shoulders – and then suddenly pushed her down.

With a grunt Rin let them, her cheeks colouring crimson as she found herself at eye-level with their crotches. The hands on her shoulders briefly left as all three men pushed their shorts right off, allowing their cocks to spring out into the open – each of them above-average in size. Rin blushed deeply but found her body reacting on automatic, the Geis edging her to act and pleasure them, to fulfil her end of the contract after she failed the last one.

The three men stood in a loose semi-circle in front of her, allowing Rin to grasp the cock on the left and right, shuddering as she slowly began to stroke their dicks. The two men moaned, but the third one shifted closer, poking her in the face with his girth. The twin-tailed girl grimaced a bit but obediently leaned in, opening her mouth and taking the tip inside – groaning deeply as she sunk her head down the old man's cock.

''Mmph...'' Rin was inexperienced but it wasn't hard to figure out how to move; groaning as she slid her lips up and down the top-half of his cock.

Rin kept sucking the man off for nearly a minute, moving both her hands at the same time – jerking off the two older men as they moaned her name. Soon she popped her lips off and shifted over to the leftmost cock, taking that one into her mouth and sucking it off instead; swapping her left hand over to the middle dick and stroking it instead. It throbbed on her tongue as she sucked it, the feeling making her shudder yet not stop her movements, her lips growing wet with her own saliva as she kept slurping the man's cock.

After nearly a full minute she pulled her lips off with a long exhale, shifting over to the rightmost cock instead – slowly taking it into her mouth while shifting her hands over to the other two dicks. By now she had gotten used to the movement and managed to take the man's cock in deeper, dimly aware of the camera focusing in on her face, recording how she slurped the old man's shaft with quick rolls of her head, her wet mouth leaving the man's cock coated in glistening-wet saliva.

''Mm... Mmph...'' Rin shut her eyes, letting her body guide her.

Over and over again she swapped between the three men, sucking and slurping their cocks even as salty pre-cum teased her tongue, their low groans of pleasure sending increasingly-aroused shivers through Rin, the humiliation of the whole scenario igniting something dark and embarrassing inside her. Their cocks throbbed more and more in her hands and in her mouth, only encouraging Rin to keep pleasuring them, to focus on just making them cum for the camera and getting it over with.

She wasn't disappointed. She put her lips on the middle man's cock and began sucking just as the man on her right bucked his hips forth – and he came. Thick ropes of cum hit the side of her face and elicited a startled yelp from Rin, forcing the magician to close one eye as his thick cum covered her cheek and got in her hair. His dick got slippery from the cum on it and she let it go, still jerking off the man to her left; until he too suddenly came with a deep moan, unloading smaller spurts of cum onto her shoulder and breasts, his cum hot against her skin.

''Mn... Mm...!'' Rin shuddered and released his cock too; focusing solely on the one in her mouth as she sucked it.

The old man above her moaned, laying both his hands on her head – before he grabbed her twin-tails. Rin had exactly half a second to widen her eyes in shock before the man roughly slammed his cock down her throat, moaning loudly as he lustfully began to face-fuck her, his pelvis smacking her nose powerfully as he pounded her throat with bestial passion. He moved so fast and hard she could barely even gag, able to only grunt and gasp between deep-throats-

-until with a loud gasp the man came, slamming his cock into her mouth and cumming straight down her throat. She couldn't even taste his cum because it went past her tongue, allowing her to only feel his thick cum dribble down her throat and into her stomach; the gross sensation making Rin shiver.

''K-Kuh...'' The magician coughed as the man pulled back, his cock slipping out of her mouth. She didn't say anything since the camera was on, but she gave him a _very_ angry glare, to which the man smiled sheepishly at her.

Rin huffed, standing back up, She shuddered as one of the man laid his hand on her lower back and pushed her, prompting her to slowly walk towards the bed as directed, blue eyes sharp as she sat her butt down onto the edge. The camera floated closer and in the background, out of view, one of the men gestured for her to lift her skirt up. With blushing cheeks Rin obeyed, gazing up into the camera as she showed off her lacy red underwear, her panties slightly damp with arousal.

One of the old men approached and 'helpfully' peeled them off her hips, dragging them down her slim legs and throwing them aside, taking the time to take her shoes off too. The man eagerly began to stroke his still-hard cock at the sight of her smooth, wet pussy, much to Rin's embarrassment. Unconsciously her legs crossed, hiding her pussy, but the man merely grasped her thighs and spread them wide open, giving him an uninhibited view of her womanhood.

Rin glared at him. ''Are you going to put it in or just stare?''

The old man smiled at her, conceding. He shifted up to the edge of the bed and pressed his cock up against her pussy, before slowly pushing his shaft inside her. Immediately Rin gasped, irritation melting into a mixture of pleasure and discomfort, intimately feeling his girth spreading her tight insides apart. The man let out a groan of his own, both his hands flying to her hips and holding onto her tightly as he buried more of his cock inside her, filling her pussy up greedily.

''Nn...'' Rin grunted lightly, grimacing as she got used to the strange feeling. She wasn't one to really care about virginity and all that; but the feeling of having a cock in her was still a weird sensation.

Mercifully the old man wasn't an asshole; he gave her a few moments to get used to having his dick inside her. When he started to move he did it slowly, his cock sliding halfway out before pushing back inside with equal slowness, the almost-gentle movements extracting a low groan from Rin's lips, pleasure tingling in her pussy. Every bolt of pleasure that hit her made her insides tighten around his dick, in turn enticing the man to move a little faster, his shaft plunging into her wet folds with increasing eagerness.

The camera hovered overhead, zooming in on her pussy as the man fucked it, his shaft sheathing itself into her dripping entrance. Rin endured the sensation with a groan, gripping the sheets as she was fucked for the first time – her eyes locked onto her own womanhood as she watched it happen. Movement to her right however forced her to look aside, blushing deeply as one of the other men knelt down next to her, his erect cock hovering in her face.

''Mn...'' Rin swallowed and sat up on her elbows, leaning her head over as best she could when she was currently getting fucked raw. ''Geez...''

Her lips touched the man's cock and he greedily pushed it into her mouth, moaning happily as she began to suck it. Rin cringed at the sound but the Geis pushed her to keep sucking the man off, grunting and groaning around his girth as the man between her legs fucked her faster – his shaft sliding in and out of her wetness with quickening thrusts. Her wetness combined with the lingering saliva on his dick helped him plunge into her pussy with impunity, and as he got more into it the older man gladly began to fuck her roughly, soon bottoming out inside her formerly-virgin pussy.

Skin slapped against skin as her pussy was fucked, each rough impact against her pelvis making her whole body jerk slightly, the bed rocking beneath her body. It became a challenge to keep sucking the cock in her mouth but the man helped her along, one hand gripping her hair and lustfully shoving his cock down her throat, moaning as he face-fucked her with awkward, rough thrusts, her non-existent gag reflex allowing him to have his way with her.

''O-Oh god...'' The man between her legs moaned, pounding his cock into her wet sex with increasing passion.

Rin merely groaned in reply, feeling his cock throb more and more as he continued to fuck her. She could feel her own orgasm twisting at her insides but not fast enough, dimly realising the man was going to cum before she could finish. She distracted herself from such an embarrassing thought by sucking the other man's cock, feeling him too twitch in her mouth as he neared his limit, his back-to-back orgasms draining him of his stamina.

And soon he reached his limit – a harsh grunt escaping him. ''Nn!''

Without warning he pulled on her hair and slammed his cock down her throat, eliciting a muffled gasp from Rin – her eyes widening as he came right down her throat. She hastily swallowed between laboured gasps, sucking in air the second he pulled out of her mouth and moaning when pleasure twinged in her pussy, her clit aching for some attention too. The skin-slapping sex however lasted for only a few more moments before the man between her legs reached his limit; suddenly slamming balls-deep inside her and cumming with an explosive moan, his load shooting inside her dripping, quivering folds.

''Ugh...'' Rin shuddered at the sensation, intimately feeling his warmth shoot inside her. ''Gross...''

Despite her words Rin didn't look that against the feeling; her cheeks flushed and her breathing heavy, giving her an almost-lustful look. The men certainly didn't seem to think she disliked it, grinning breathlessly at each other as the one between her legs pulled out, his cock glistening with their mixed fluids.

He stepped back and let the other two older men move in, allowing one to grab Rin by her underarms and pulling her a little further back onto the bed, unheeding of her low groan. They tugged her onto all fours and Rin begrudgingly assumed the position, blushing red as she had to spread her legs a bit, showing her wet pussy to the camera. Mercifully it was hidden as one of the men got behind her, his distinctly-wet cock rubbing against her sensitive folds – before he plunged inside her.

''Mm!'' Rin moaned out; immediately slapping a hand over her mouth in embarrassment.

The second older man knelt down in front of her, the bed shifting beneath her hand. He pulled her clasping hand off her mouth and instead pushed his dick into her face, smearing the fluids on it against her lips and prompting Rin to reluctantly open her mouth – groaning as she slid her lips down it. She managed to take nearly his full length on the first go and immediately began to suck him off, bobbing her head as best she could.

A low groan came from behind her as the other man grabbed her hips, greedily pushing his cock into her womanhood. With how wet she was there was zero pain, his cock fitting snugly inside her tight pussy as he began to move immediately, his shaft sliding back and forth with rhythmic rolls of his hips. He started slow at first but began to pick up speed quickly, his lust easily apparent as he started fucking her raw, his wet shaft slickly sliding into her pussy.

''Mm! Mmph! M-Mn~!'' Rin moaned around the cock in her mouth, shuddering as she was spit-roasted between the two men – her whole body growing hot from the constant sex and arousal.

From the corner of her eye she could see the camera orienting around to get a side-view of her, causing a deep blush to coat her cheeks – doubly so when the man fucking her mouth reached down and unclipped her bra, allowing it to fall off and exposing her medium-sized boobs; her tits jiggling as she was fucked back and forth. Her pussy tingled with fresh arousal, the thought of others watching the film and seeing her getting railed strangely turning her on.

_'Oh god.'_ Rin flushed a deep crimson. _'I-I can't... be liking this?!'_

The humiliating thought fuelled the excited burn in her pussy, confirming her dawning realisation. However she was given no time to contemplate it; both men groaning as they pounded her mouth and pussy, fucking her throat and hitting her cervix with each passionate thrust. Rin moaned from the sensation, her inner walls tightening around the cock pounding her from behind as she felt the pleasure build and build, her own orgasm rapidly swelling up inside her.

To add fuel to the fire the older man's pelvis smacked her ass each time he bottomed out, the impact so rough and quick it was like a spank, tapping into her previously-unknown masochistic tendencies. Her pussy quivered around the cock pounding it, her honey dribbling down her inner-thighs and wetting her black stockings, her moans taking on a distinctly-lustful edge as she began to get into it, her pride crumbling in the face of the debauched pleasure of being so utterly fucked.

''Mm... M-Mm! Ahm-'' Rin tightened up as the pleasure reached its apex. '' _Mmph!_ ''

With a muffled cry of orgasmic pleasure Rin finally hit orgasm, cumming on the man's cock. Her honey squirted out from around his cock, eliciting a low moan from the older man as he pounded her for only another few seconds; his moan becoming a deep groan as he slammed all the way inside her and blew his load, cum painting her seizing inner walls white.

The other man didn't last any longer, a harsh grunt escaping him as he suddenly pulled out of her mouth; jerking himself off to completion and cumming on her face, his milky load spurting up her cheeks, over her lips and onto her forehead, leaving her face a mess by the end of it.

''Ohh~'' Rin groaned dumbly, her arms giving out from under her and sending her flopping face-first into the sheets.

The other old man pulled out of her pussy, the trio giving her a minute to compose herself – chatting amongst themselves and fiddling with the camera, acting for all intents and purposes like they hadn't just fucked her brains out. However soon coherency returned and she sat up a bit, panting, but with her stamina slowly coming back to her.

At the sight of that the men went back into action, the camera reactivating and hovering overhead, ready to keep filming. One of the men laid down on the bed and Rin groaned, shuddering as she awkwardly shifted onto his waist, feeling his cock prodding her inner-thigh. She adjusted her knees a couple times, idly grasping his cock and lining him up – before with a deep sigh Rin eased herself down the man's cock, groaning as her sensitive pussy was filled back up.

''Mn...'' Rin bit her lip, groaning through her teeth as she began to bounce – sliding herself up and down the man's hard cock.

Slowly Rin rode the man, careful at first as she got used to the motion of moving her hips. However as she got used to it she picked up speed, her breathing heavy and lustful as she impaled herself upon the man's wet cock. Her boobs jiggled about lightly and the man beneath her fixed that, grasping both her boobs and groping them, eliciting a hot moan from Rin from the pleasure. With only her skirt and stockings on the camera got a good view of her body, the little bit of clothing still hanging from her otherwise nude frame adding a certain naughty charm to it.

A surprised grunt escaped Rin as she felt the bed behind her shift – and her eyes widened as she felt the other man push his cock against her asshole. She didn't get the chance to voice her surprise before he pushed inside, melting her words down into a deep moan; her bounces stalling as he penetrated her ass. On instinct she leaned forwards a bit, planting her hands on either side of the man's head beneath her, incidentally making her breasts hang in his face.

''Ah...'' Rin shuddered; cheeks flooding red when the third man stood in front of her, his cock hanging in her face. ''Ugh...''

The tip pressed against her lips, and once more Rin took the cock into her mouth, moaning as she was triple-penetrated. The world around her bled away as she took it in her pussy, her ass and her mouth, losing herself in the friction and pleasure. Her mind grew distant and she just let her body do the work, moaning and gasping as her body was used for their pleasure, feeling her skin tingle and her breasts squish beneath their groping, squeezing hands.

In no time at all they came in her. They pumped her asshole full of seed, they shot their loads into her womanhood, they filled her throat with seed and painted her face white with cum; they did it all.

And soon they went for another position, then another, and another. They pinned her to the sheets and railed her asshole, they laid her on her side and fucked her sideways, they carried her and double penetrated her, they held her upside-down and fucked her pussy from above. They even carried her into the adjoined shower and kept railing on her there, pounding and pounding her until she went numb below the waist, nothing but buzzing pleasure registering in her thoroughly-fucked mind.

By the end of the night, Rin would struggle to crawl out of the hotel room, let alone walk. And that would be only the first day out of several weeks of her new 'assistant' position.

And strangely, she began to look forward to it. Though she fervently denied it to any who asked.

[END]


End file.
